Yeah, clear as mud!!!Using the words gold & silver are just confusing the "Birchen" issue.
The term Birchen, without saying silver, means black with silver. One doesn't have to say, Silver Birchen, because its understood that it has silver.
The gold that appears is what the Marans call " Black Copper". It is "birchen" but with the gold replacing the silver. I'm not familiar with all breeds, but I'm pretty sure no one says "gold birchen". Others use "brown red" which to me is really confusing because the brown is really black....
So, a rooster can have 2 color genes. When the variety is Birchen, and gold appears, or cream colored feathers along with or without silver, it means that the bird has both gold & silver, and is not pure for "birchen" (meaning just silver & black). If just the gold appears in Marans then it is a black copper. We don't call it gold birchen.
Clear as mud! LOL

I ask because I know of at least 5 marans breeders within a few hundred miles of me that are concentrating on producing just the "gold birchen".
Looks like it would be best on my part to pass on adding any of those to my marans flock and stick to the silver I have.

Thanks!